Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3783a2f9efc0b62…

MALICIOUS

PDF

12.0 KB
MD5: 437a721f08e59ac68e9eb7880dadb2c1 SHA-1: f14d1e0f88504309f9e05dca144614b1c21a6572 SHA-256: a3783a2f9efc0b62f678d6fbb9fb04e5fef652accdc55524154146f5f7f398ae
200 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript, indicated by multiple heuristic firings including 'PDF_JAVASCRIPT' and 'PDF_JS'. Critical heuristics like 'PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER' and 'CVE_2007_5659' point to the use of JavaScript for exploitation, specifically leveraging the 'Collab.collectEmailInfo' method to decode and execute obfuscated JavaScript. The presence of deobfuscated JavaScript files ('legacy_pdfkit_stage_000.js', 'legacy_pdfkit_stage_001.js') suggests a multi-stage attack where the initial PDF acts as a dropper for further malicious code. The ClamAV detection 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)
  • Annotation subject percent-decoding eval stager critical PDF_ANNOT_SUBJECT_MARKER_EVAL_STAGER
    OpenAction JavaScript forces annotation enumeration, reads an annotation /Subject payload with getAnnots(), rewrites marker bytes into percent escapes, decodes it with unescape(), and dispatches it through eval. This is a high-confidence exploit-kit staging pattern. It is intentionally not mapped to CVE-2009-1492 unless getAnnots() itself carries the crafted integer or long argument shape for that vulnerability.
  • ClamAV: Pdf.Exploit.Agent-36065 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-36065
  • 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 differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser exited 1. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
9c67560e8c63b720885d3efc1627b844b86a6ec08e99e5b65a22eae832045756
pdf-javascript-stream PDF /JS object 7 at offset 0x19C 431 bytes
legacy_pdfkit_stage_000.js
4797b66267828976e6387a2b1795576cfec132191fee681c270d14e33f0e3a37
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x315 12292 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
legacy_pdfkit_stage_001.js
d8b47a3bcbdde589757018c91debfe146c67e7e055cb9cbf4e6ecabf83cb0778
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x315 5039 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).