Malicious PDF — malware analysis report

Static analysis result for SHA-256 ae479de7c99bad79…

MALICIOUS

PDF

110.6 KB Created: 2010-02-07 22:10:13 +01:00 Authoring application: LaTeX with hyperref package (via xdvipdfmx (0.6))
MD5: 6b0eda4ec99480d9879144c170392231 SHA-1: b5bfa0984d91781918f6a4275c9eab7597ccfa4b SHA-256: ae479de7c99bad79adebe09dbf663d0de18b1373532ae11803b638e7cf558abe
342 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious Link T1059.003 Windows Command Shell

The PDF file contains a critical PDF_LAUNCH heuristic firing indicating a launch action. This action targets cmd.exe, which is then used to create and execute a VBScript payload. The script itself is embedded within the PDF and is likely responsible for downloading and executing a second-stage payload from the external URI http://www.foo.be/. The PDF also exhibits parser evasion techniques.

Heuristics 9

  • Launch action critical PDF_LAUNCH
    PDF contains a /Launch action whose target is an executable, URL, or UNC path — can start an external application
  • /Launch action target: cmd.exe critical PDF_LAUNCH_COMMAND
    PDF /Launch action specifies an executable target with parameters '/c echo Dim BinaryStream > vbs1.vbs && echo Set BinaryStream = CreateObject("ADODB.Stream"' — references a known-dangerous executable (cmd, PowerShell, etc.).
  • ClamAV: Win.Trojan.Dropper-134 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Dropper-134
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Embedded script payload in PDF stream high PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain script execution markers such as ActiveXObject/CreateObject, WScript.Shell, PowerShell, or shell-exec primitives. This is stronger than ordinary PDF JavaScript because it indicates a staged external script payload hidden in stream bytes.
  • Clickable PDF combines external action with parser-evasion structure high PDF_ACTION_PARSER_EVASION
    PDF has an external clickable URI together with object graph or xref structures that make parsers disagree, such as divergent duplicate objects, parser divergence, or xref offset mismatch. That combination is stronger than a plain link: the document is both an outward-action carrier and a parser-confusion/evasion sample.
  • Suspicious extracted artifact medium 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.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.foo.be/
    • http://www.gitorious.org/~adulau

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_pdf_script_0000ddf7.bin
f7da54c1c4956dd6529949e1bac1dcb9cfa4c01672bc6a3b6dd50b7ba46cd9bd
pdf-embedded-script PDF decompressed stream script payload at offset 0xDDF7 113213 bytes
Detection
ClamAV: Win.Trojan.Dropper-134
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s). Carved artifact contains 2 long base64-like blob(s).
font_00_cff_off00003d8a.bin
09e18e495b68106a55aace3f441183e73b28de0f6fbcb0af0b76d08e38de00da
pdf-font-stream PDF embedded font (cff) at offset 0x3D8A 15636 bytes
font_01_sfnt_off00007386.bin
1bbf8d898c7de34b2ed1bfb68d2725a06e3c5e09957aee601794b4fe88adb9f4
pdf-font-stream PDF embedded font (sfnt) at offset 0x7386 13054 bytes
font_02_cff_off00009b0d.bin
81cd2ec160f0dbbfecf3a7282aa50fb69c8be6a3e42aa5a6d27c573cc7517a2e
pdf-font-stream PDF embedded font (cff) at offset 0x9B0D 7529 bytes
font_03_cff_off0000b8d9.bin
19f70b70255abac1a93513d95c8ae661c9f9d2f99400a22c24727869e919e5ad
pdf-font-stream PDF embedded font (cff) at offset 0xB8D9 7369 bytes