Malicious PDF — malware analysis report

Static analysis result for SHA-256 4d3d8e28ae8a311f…

MALICIOUS

PDF

17.6 KB
MD5: 3b6441008574040f343668d8077d12f6 SHA-1: b7f14640869e0d82c31bbcba7e96ea8405218e54 SHA-256: 4d3d8e28ae8a311f637557a28ebe7f45505451427007be01791fac5b9da1df0a
194 Risk Score

Malware Insights

MITRE ATT&CK
T1204.001 Malicious Link/Object T1059.001 PowerShell

This PDF file exploits CVE-2007-5659, a vulnerability in Adobe Reader related to the `Collab.collectEmailInfo` function. The critical heuristic `PDF_JS_OBFUSCATED_DROPPER` indicates that the embedded JavaScript is obfuscated and acts as a multi-stage dropper. The `CVE_2007_5659` heuristic specifically points to the exploit trigger and the encoded payload. The presence of multiple JavaScript streams and deobfuscated JavaScript files further supports the malicious nature of the document, which is designed to download and execute a second-stage payload.

Heuristics 8

  • 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-35901 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Exploit.Agent-35901
  • Obfuscated multi-stage PDF JavaScript dropper high PDF_JS_OBFUSCATED_DROPPER
    PDF JavaScript shows 4 independent signals of exploit-kit-style multi-stage obfuscation: annot_subject_stage, hex_codec_loop, incremental_eval_build, repeated_pluginschk. This is strongly consistent with pre-2011 Adobe Reader PDF droppers — OpenAction JS reads encoded data from annotation subjects, decodes it through one or more hex / base-N loops, and invokes eval indirectly (method name built one character at a time). The actual CVE is hidden in the final decoded layer and is not visible via static analysis.
  • 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.
  • String.fromCharCode low PDF_FROMCHARCODE
    String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules. (matched inside decoded stream)
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0009_000.js
4718a27c2224fc36bf24f8e8e04598f1ad78adce4401c7be2708318738a6983d
pdf-javascript-stream PDF /JS object 9 at offset 0x441E 469 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).
legacy_pdfkit_stage_000.js
2be431776171fc25d305939540ba7379c339a3f7daa5ab99e4c87e500a5b77f4
deobfuscated-js z-percent UTF-16BE base-21 decoded JavaScript at offset 0x1AF4 5322 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
deobfuscated.js
a32151b7a1bf7050005432471aaf1b68a9bec88698634c3334b47158f47dd99a
deobfuscated-js PDF JavaScript deobfuscation pass 179282 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 2 long base64-like blob(s).