PDF malware analysis — malicious · 0261a2cd75be5aa8

MALICIOUS

PDF

14.9 KB Created: 2009-06-06 12:30:26 +03:00 Authoring application: NitroPDF 6.0 (via BCL easyPDF 6.00.20)

MD5: c68b8df28ee16cf13fe11e5eabc84ad6 SHA-1: 364dd1b604c59b21be00e4a48894a2322c9b0d48 SHA-256: 0261a2cd75be5aa8f8b5a7209d6df9128e36b5cc4111a7f5cc5f5d07745dab7e

692 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains heavily obfuscated JavaScript that exploits multiple known Adobe Reader vulnerabilities. The script is designed to download and execute a second-stage payload from the URLs provided. The presence of multiple CVEs and the shellcode download URL strongly indicate a malicious dropper.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 17

Collab.getIcon — CVE-2009-0927 critical CVE exact CVE_2009_0927

PDF JavaScript calls Collab.getIcon — CVE-2009-0927 is a stack buffer overflow in Adobe Reader triggered by Collab.getIcon() with a crafted argument. Allows arbitrary code execution. (identified after JavaScript deobfuscation)
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 JavaScript deobfuscation)
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.
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.
Multi-CVE Adobe Reader JavaScript exploit kit critical PDF_ADOBE_READER_MULTI_CVE_JS_KIT

One recovered JavaScript stage contains multiple version-gated Adobe Reader exploit branches. This is stronger evidence than independent API keywords: the PDF is selecting old Reader vulnerabilities by viewer version and running heap-sprayed Acrobat JavaScript exploit paths.
ClamAV: Pdf.Dropper.Agent-7222639-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Pdf.Dropper.Agent-7222639-0
ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV

ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
eval() call high PDF_EVAL

eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
Shuffled variable-fragment JavaScript stager high PDF_SHUFFLED_VAR_JOIN_JS_STAGER

PDF JavaScript stores an exploit stage as many randomly named string fragments, rebuilds the fragment order through a name array and eval(join('+')), then decodeURIComponent/evals the result. The decoder requires a large variable table and only fires when the recovered stage contains concrete Acrobat exploit JavaScript.
Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY

Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL

Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. 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).
JavaScript action low PDF_JAVASCRIPT

PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
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.
PDF paints image(s) but contains no text operators info PDF_IMAGE_ONLY_LURE

PDF has 1 image XObject(s) and the content stream contains no text-emitting operators (BT/ET, Tj, TJ, ', ") in either raw bytes or decompressed streams — this is the screenshot-as-PDF pattern used to bypass text-based scanners and to deliver instructions purely through rendered pixels. It is informational unless paired with invisible links or risky URI context.
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://vkontalte.cn/info/getexe.php
- http://vkontalte.cn/info/getexe.ph
- http://vkontal

Extracted artifacts 6

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0015_000.js` `f7462507deec0545f8133fc2b04ae0c59a17d0cad9f9739c1b01e86b87971441`	pdf-javascript-stream	PDF /JS object 15 at offset 0x315	29100 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 eval/decoder/string-building token(s).
`shuffled_var_join_stage_000.js` `4e09311323771e81576e4556c546f37e84598aff356078f946b9ddde74bf4d79`	deobfuscated-js	shuffled variable-fragment join decoded JavaScript object 15 at offset 0x4BA5	4981 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 7 eval/decoder/string-building token(s).
`shuffled_var_join_stage_001.js` `c61a605da24f11a3933b99203c38cafa50d7e60e4471dcd12757dff317e0d53b`	deobfuscated-js	shuffled variable-fragment join decoded JavaScript object 15 at offset 0x4381	5329 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`shuffled_var_join_stage_002.js` `670e2f2428f40c4410d8a1918152ca57f8fef6b1c430704dfd20cc60e842146e`	deobfuscated-js	shuffled variable-fragment join decoded JavaScript object 15 at offset 0x4381	4979 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 7 eval/decoder/string-building token(s).
`generic_stage_recovery_000.js` `3eecf76555396d78d5c35b84e55443d9bb8bc9cb35414b1ec008ed72303b723f`	deobfuscated-js	generic stage recovery percent-decode from JavaScript object 15 at offset 0x315	27016 bytes
Detection ClamAV: Js.Exploit.Shellcode-18 Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).
`generic_stage_recovery_001.js` `ce62a8c3e4a430a30c5d424db2598fd890c3d8b652cee71f006b009974d688ed`	deobfuscated-js	generic stage recovery percent-decode -> percent-decode from JavaScript object 15 at offset 0x315	27014 bytes
Detection ClamAV: Js.Exploit.Shellcode-18 Obfuscation or payload: likely Carved artifact contains 5 eval/decoder/string-building token(s).

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