Malicious PDF — malware analysis report

Static analysis result for SHA-256 83af2d7aecbb8b07…

MALICIOUS

PDF

12.2 KB
MD5: a98943891cc8e1e08b6a5e7039dd739a SHA-1: aeec6e36049638420417ca5bf297e019fce617b4 SHA-256: 83af2d7aecbb8b0737e6ccf31d0d837df79077f5f9b1dad7e41172c7d90a0f64
186 Risk Score

Malware Insights

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

The file is a PDF document that leverages the CVE-2007-5659 vulnerability, specifically targeting the 'Collab.collectEmailInfo' function. This exploit triggers the execution of a JavaScript stager. The stager is heavily obfuscated but ultimately appears to be designed to download and execute a second-stage payload. The presence of multiple deobfuscated JavaScript files indicates a complex multi-stage attack. The ClamAV detection of 'Pdf.Exploit.Agent-36063' further confirms its malicious nature.

Heuristics 7

  • 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-36063 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36063
  • 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
eb39e2de4dbbc100de6d3e30aa43ff78fa075618862ba1ebba5151ea3a3b848d
pdf-javascript-stream PDF /JS object 7 at offset 0x19D 273 bytes
annotation_subject_callee_hex_stage_000.js
879ee6d387a7651241528b800652fee25bc8bd8c8031eb3e0da542b333a9046c
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5204 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
1b44c05863bab0315e140a3a420d0c4ed8c09a6723c98e71395a1ce4e194a296
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2D6 12427 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
08f1e99e6e6bc49da730f9016d1d4109a531eec64c80497183882cf43f901ba2
deobfuscated-js PDF JavaScript deobfuscation pass 78926 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).