Malicious PDF — malware analysis report

Static analysis result for SHA-256 a52600dc4b6295df…

MALICIOUS

PDF

9.1 KB
MD5: 0fb0d59791ed48aef2ac0e60badf2eb6 SHA-1: 54cf19ae97c5b215614653c122700fe53ef5b8a2 SHA-256: a52600dc4b6295dfe7dd9e8d18bb3ca4bae831e7dd17560b25e11d1035750141
266 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

This PDF file contains multiple embedded JavaScript streams, with critical heuristics indicating the use of `eval()` and `unescape()` for obfuscation. The `CVE_2007_5659` heuristic specifically points to the exploitation of a known PDF vulnerability via the `Collab.collectEmailInfo` method, which is used to stage and execute JavaScript. The presence of large, deobfuscated JavaScript files suggests the execution of complex malicious code, likely for downloading and executing further stages. No specific family could be identified, but the exploit pattern is clear.

Heuristics 9

  • 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)
  • ClamAV: Pdf.Exploit.Agent-35912 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35912
  • 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)
  • Annotation subject callee-key hex JavaScript stager high PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER
    PDF JavaScript uses syncAnnotScan()/getAnnots() to read an indirect annotation /Subject stream, percent-decodes it through marker replacement, then uses a callee.toString()-derived key to decode and eval the final exploit stage.
  • 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.
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed stream)
  • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
7218a1c68060953321573daa035b16f5f32928ce25a9eb656690dbe78cd9464e
pdf-javascript-stream PDF /JS object 7 at offset 0x19B 201 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
annotation_subject_callee_hex_stage_000.js
7eb33c7ea5fef6e04f76f9ea910f5c72cd813755a8d5f92a560a72c3c06dc508
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5045 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
b7314d60d98faf579222dc8a6f4aab87999a1b3eeb821b9c78ab4a70b01c7a1a
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2B5 11881 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
be49f26f7d10c04ecdb84709af51f867120f1d22c9f1c308097549a0b9721c49
deobfuscated-js PDF JavaScript deobfuscation pass 42178 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).