Malicious PDF — malware analysis report

Static analysis result for SHA-256 051b5ad3b078fe3e…

MALICIOUS

PDF

7.4 KB Authoring application: Viraciregavi
MD5: 4c6091737f9fbbd50aadf2263f03cc85 SHA-1: b573f527b8a0444aeae6d87007b46bbd79f8f3dc SHA-256: 051b5ad3b078fe3e71241ba7150f6e1d0300acfa0df3d5f84f7123561be891d2
468 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.007 JavaScript

The PDF file contains embedded JavaScript that utilizes multiple known exploits targeting Adobe Reader, specifically related to Collab.getIcon, Collab.collectEmailInfo, and util.printf functions. The script is heavily obfuscated but static analysis successfully recovered exploit triggers and identified it as a generic stage recovery mechanism, strongly indicating its purpose is to download and execute a secondary malicious payload. The ML classifier and ClamAV detection further corroborate the malicious nature of this PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 11

  • 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)
  • 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.
  • ClamAV: Pdf.Exploit.Agent-35649 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35649
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • unescape() call high PDF_UNESCAPE
    unescape() found — often used to decode shellcode in PDF JS exploits (matched inside decoded stream)
  • 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.
  • 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.
  • 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.

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
8913193fb116595486d78a2023b6e80c0a20f49e34ebfa9ed3419eeee374ae31
pdf-javascript-stream PDF /JS object 7 at offset 0x45A 5781 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 11 eval/decoder/string-building token(s).
generic_stage_recovery_000.js
491a3160d24d9625ee5085776cedd3eefc12fe7f97dddcaa63b29d0e7a01fe82
deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 7 at offset 0x45A 5514 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 11 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
generic_stage_recovery_001.js
8014553da6f3531d4103e9a201fa84ac04c0ab07643d56223e770b8009b850c4
deobfuscated-js generic stage recovery split-literal-normalize from decompressed stream at 0xED7 at offset 0xED7 2882 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 11 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
generic_stage_recovery_002.js
d02572d6084b4d75ea740332de84bd64d1805f342fe6a7040d2c28d3f1518530
deobfuscated-js generic stage recovery split-literal-normalize from decompressed stream at 0xED7 at offset 0xED7 2851 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 11 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
generic_stage_recovery_003.js
db079d9b98c395a3dc7164cfe5da1f807907311113015940e0334c35aaf02092
deobfuscated-js generic stage recovery split-literal-normalize -> percent-decode from JavaScript object 7 at offset 0x45A 5510 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 11 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
generic_stage_recovery_004.js
c98a0eed40d181a5d31166ff7e02d0dae04bb30106a4f8847c6aeffa5fd281f6
deobfuscated-js generic stage recovery percent-decode -> split-literal-normalize from JavaScript object 7 at offset 0x45A 5512 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 11 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
legacy_pdfkit_stage_000.js
1e0c8ca4c6180400afd62497a161d41969b04e1091a2d4ffa9764c7f00cf51a1
deobfuscated-js string-concatenation normalized Acrobat API aliases at offset 0x45A 851 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 long base64-like blob(s).